Question

Which of the following are Brønsted-Lowry bases? (a) \(\mathrm{SO}_{3}^{2-}\) (b) \(\mathrm{Ag}^{+}\) (c) \(\mathrm{F}^{-}\)

Short answer

\( \mathrm{SO}_{3}^{2-} \) and \( \mathrm{F}^{-} \) are Brønsted-Lowry bases.

Step-by-step solution

Identify Brønsted-Lowry Base Definition

A Brønsted-Lowry base is defined as a substance that can accept a proton (H⁺ ion). Keeping this definition in mind, we'll evaluate each given substance to determine if it can accept a proton.

Evaluate \\( \mathrm{SO}_{3}^{2-} \\\)

The sulfite ion \( \mathrm{SO}_{3}^{2-} \) has the potential to accept a proton, forming \( \mathrm{HSO}_{3}^{-} \). This reaction shows that it can act as a Brønsted-Lowry base.

Evaluate \\( \mathrm{Ag}^{+} \\\)

Silver ion \( \mathrm{Ag}^{+} \) does not have any capacity to accept a proton, as it is positively charged and tends to form cationic species. Hence, it cannot be considered a Brønsted-Lowry base.

Evaluate \\( \mathrm{F}^{-} \\\)

The fluoride ion \( \mathrm{F}^{-} \) can accept a proton to form \( \mathrm{HF} \). This means it can act as a Brønsted-Lowry base.

Conclusion

Overall, after evaluating the capability of each substance to accept a proton, \( \mathrm{SO}_{3}^{2-} \) and \( \mathrm{F}^{-} \) are both classified as Brønsted-Lowry bases.

Key concepts

Proton Acceptor

In the realm of chemistry, the term "proton acceptor" is crucial to understanding various reactions. A proton ( ext{H}^+) is essentially a hydrogen atom lacking an electron, which makes it positively charged. In the context of Brønsted-Lowry theory, a proton acceptor is a substance that can receive an ext{H}^+ ion during a chemical reaction. This ability to accept protons defines a Brønsted-Lowry base.

When a molecule or ion serves as a proton acceptor, it undergoes a transformation. For example, it might change its structure or form a new compound. The process enhances the compound's chemical properties through the formation of new bonds.

A key factor in this transformation is the presence of available electron pairs on the acceptor species. These electron pairs can form a chemical bond with the ext{H}^+, stabilizing the newly formed species. Understanding proton acceptance helps us predict the behavior of chemical reactions and the formation of products.

Acid-Base Chemistry

Acid-base chemistry is a fundamental part of understanding how reactions occur in aqueous solutions and beyond. According to the Brønsted-Lowry theory, an acid is defined as a substance that donates a proton ( ext{H}^+), while a base is defined as a proton acceptor. This classification helps us understand how substances can interact with one another in a variety of reactions.

Important principles of acid-base chemistry include:

• Equilibrium: Many reactions reach a state where forward and reverse reactions occur at equal rates, known as dynamic equilibrium.
• pH Scale: This scale measures the acidity or basicity of a solution, based on the concentration of hydrogen ions in the solution.
• Conjugate Acid-Base Pairs: When an acid donates a proton, it becomes its conjugate base, and when a base accepts a proton, it becomes its conjugate acid.

Understanding these concepts is vital for predicting the outcomes of acid-base reactions and their effect on system properties.

Sulfite Ion

The sulfite ion, denoted as ext{SO}_{3}^{2-}, is a significant player in acid-base chemistry due to its ability to function as a Brønsted-Lowry base. With its two negative charges, the sulfite ion is predisposed to attract and accept a proton ( ext{H}^+).

When the sulfite ion accepts a proton, it transforms into hydrogen sulfite ( ext{HSO}_{3}^{-}). This altered form acts as its conjugate acid, displaying the classic acid-base pairing as per the Brønsted-Lowry model.

The acceptance of protons by sulfite ions is of practical importance:

• In environmental chemistry, sulfite compounds are often used in pollution control.
• They play roles in various industrial processes, such as water treatment and food preservation.

The sulfite ion exemplifies how the principles of acid-base chemistry are applied in real-world scenarios.

Fluoride Ion

The fluoride ion, represented as ext{F}^{-}, is well-known for its role in oral health products. However, it is also a classic example of a Brønsted-Lowry base. The fluoride ion, with its single negative charge and high affinity for protons, readily accepts an ext{H}^{+} ion to form hydrogen fluoride ( ext{HF}).

This characteristic is key in many chemical reactions. For instance, the fluoride ion's ability to accept protons makes it useful in etching glass and in organic synthesis, where it serves as a catalyst or reactant.

In terms of everyday applications, the fluoride ion:

• Helps to reduce tooth decay by assisting in the remineralization of enamel.
• Is used in some water fluoridation processes to promote dental health.

Understanding the fluoride ion’s role as a proton acceptor underscores its importance in both chemistry and health-related fields.